Sunday's episode of "Downton Abbey" on PBS featured a guest appearance by one of opera's biggest living talents: Dame Kiri Te Kanawa. The New Zealand-born soprano played Dame Nellie Melba, an actual opera singer who hailed from Australia and whose career spanned the late 19th and early 20th centuries.

"Downton" portrays Melba as a guest performer of the Crawley household, serenading the family after dinner with the aria "O Mio Babbino, Caro" from Puccini's opera "Gianni Schicchi."

The events of the fourth season of "Downton Abbey" take place in 1922. Puccini wrote "Gianni Schicchi" just a few years before in 1918, making it a relatively new piece of music as far as the Crawley family is concerned.

Melba -- whose real name was Helen Porter Mitchell -- was famous for her diverse repertoire, including Mimi in Puccini's "La Boheme." The singer was one of the biggest opera stars of her generation and even had the tea-time snack Melba toast named in her honor.

In Sunday's episode, the old-fashioned Earl of Grantham (Hugh Bonneville) is portrayed as being somewhat nervous about housing a singer in his estate, and decides to confine Melba to her room until after dinner. But his wife, Cora, will have none of it, and summons the singer to join them for dinner.

The Telegraph's opera critic Rupert Christiansen faulted the episode, writing that Melba would never have tolerated such treatment from her hosts. He also criticized Te Kanawa's singing, singling out her "sharp unsteady intonation, heavy vibrato and tastelessly swooping portamento."

Fans of Te Kanawa may remember that she memorably sang "O Mio Babbino, Caro" on the soundtrack for the 1986 movie "A Room with a View," which starred "Downton Abbey's" Maggie Smith.